1. Field of the Invention
The present invention relates to a three-dimensional printing method.
2. Description of Related Art
Following the development of technology, various approaches have been proposed to establish physically three-dimensional (3-D) models by using additive manufacturing technology such as layer-by-layer model construction. Generally, additive manufacturing technology transforms the design information of 3-D models built by the modeling software or computer-aided design (CAD) into multiple thin (quasi two-dimensional) cross-section layers to be successively stacked.
Currently, a number of methods have been developed to form multiple thin cross-section layers. For example, printer head usually moves along X-Y coordinate above the base according to X-Y-Z coordinate from the design information of 3-D models, and then it sprays the build material in the correct shape of cross-section layers. Afterwards, the deposited material is naturally harden or solidified by a strong light source to become the desirable cross-section layers and to form the three-dimensional object through layer-by-layer solidification. Depending on the property of the build material, different methods may be used to form the 3-D models. For example, some methods, such as selective laser sintering (SLS) and fused deposition modeling (FDM), melt or soften the plastic material as the “ink” for printing to produce the layers. Besides, other methods, such as stereolithography (SLA) and laminated object manufacturing (LOM), use liquid materials as the “ink” for printing. The printer reads the cross-section information from the files and prints out these cross-sections layer-by-layer with liquid, powder or sheet form materials to build the model by adhering a series of cross-section layers together. Such technology is known for possibly forming the objects in any shape.
No matter whichever forming method is used to perform three-dimensional printing, it is necessary to concurrently print out supporting structures between the overhanging portion and the base for the existing three-dimensional printing processes, if the expected three-dimensional object has the overhanging portion, namely, there is space existing between the overhanging portion and the base. The supporting structure aims to avoid stress concentrated at the overhanging portion of three-dimensional object, thus leading to deformation. After completing the three-dimensional printing process, the aforementioned supporting structure will be removed from the three-dimensional object.
As the aforementioned supporting structure is merely used to support the three-dimensional object and has to be removed later, the supporting structure can not be reused and will be wasted. The more overhanging portions the three-dimensional object has, the more supporting structures are needed. As a result, more materials are wasted, longer time is need to build the model and the efficiency of three-dimensional printing is lowered.